Carburetor



May 26, 1931.

B. BEARD 1,806,930

- QCARBURETOB f Filed Feb. 11, 1929 I s Sheets-Sheet 1 .Zzmr Jar/w IN V EN TOR.

A TTORNE Y.

May 26, .1931. B. BEARD 7 .930

I CARBURETOR Filed Feb. 11, 1929 s Sheets-Sheet 2- z mm? /v M May 26, 193 1. BEARD 1,806,930

CARBURETOR Filed Feb. 11; 1929 5 sheets-sheet 5 ATTORNEY.

g k EILW- Patented May 26, 1931 UNITED STATES" PATENT OFFICE BERT BEARD, F DETROIT, MICHIGAN, ASSIGNOR TO GEORGE M. HOLIIEY, OF DETROIT,

MICHIGAN OARBURETOR Application filed February 11, 1929. Serial No. 338,934.

The object of this invention is to secure the maximum degree of filling with the minimum disturbance to the mixture ratio during the transition periods when both speed and load are changing.

Figure 1 is a cross-sectional elevation on plane 11 of Figure 2.

Figure 2 is a cross-section on plane 22 of Figure 1 showing the accelerating means.

Figure 3 is a cross-sectional elevation on a plane parallel to plane 11 showing the low speed fuel well. i v

Figure 4 is adetailed view of the priming means.

Figure 5 is. a diagrammatic sketch showing just where each fuel connection enters the fuel nozzle.

In the figures, A is the air entrance, in which is mounted the choke valve S, B is the Venturi tube; C is the mixing tube located concentrically in the throat of the Venturi tube. K is the constant level fuel supply chamber and D is the fuel nozzle fed therefrom and discharging into the center of the mixing tube; E is the throttle located in the mixture outlet F. G is the throttle rod to which is attached the linkage H1, H2 and H3.

The link H3 is pivoted at H4 and engaged at H5 with a fuel valve J (see Figure 2). This valve J also admits fuel from the float chamber K to the fuel nozzle D. This fuel nozzle D consists of a threaded lower portion having fuel openings D2 and D3 and air openings D1 and D4 suitably separated from each other by shoulders. The fuel entering past J issues into D through the opening D2. Figure 2 illustrates the accelerating means comprising the linkage H1-H6. The extreme end,

H6, of H3 engaged with a fuel pump L com- 40 prising a piston L1, check valve L2 and pis:

ton rod L3 adapted to slide freely through the center of the piston L1. The rod L3 is threaded into an inverted piston L5 which engages with the end of the link H6. A very flexible spring L4 transmits motion from L5 to L1. A stiffer spring L6 insures the return of L5 by engaging with the underside of L5 and with anabutment L7 located in the cylinder of the fuel pump L. The fuel displacedout of L discharges frornthe high speed fuel nozzle M which is threaded into the center of the main fuel nozzle D. Fuel is also admitted into the nozzle D from three additional sources, namely, as follows 1. Direct from the float chamber through the restriction'N (Figure 3) which communi cates with the opening D3 which also supplies fuel to the low speed well WVl which is vented at 72 to the atmosphere through VVil.

2. Through the manually adjustable valve 0 which also admits fuel from the floatchamber K to the opening D3 in the nozzle D.

3. Through the priming fuel valve P which is raised by the link Q, which engages with the shaft R upon which is mounted the choke valve S (Figures 4 and 1').

Fuel admitted through P by the opening of the needle flows from the float chamber to D2. Air is admitted to the nozzle D through the passage T and the restriction U which communicates with the upper portion of the float chamber K which is vented to the outside'air through V. The low speed fuel passage W which is fed from the orifice N delivers fuel adjacent to and in advance of the throttle E in a well known manner. The valve W5 shown in elevation in Figure 2 controls the amount of this low speed fuel. These fuel connections are all clearly shown in Figure 5.

Operation On starting the engine to which this carburetor is attached, the choke valve S is closed thereby raising the valve P through the link Q operated by the cam R, which is integral with the shaft of choke valve S (Figure 4). The fuel is thereby increased at the same time .that the air flow is reduced. On opening the from the restriction U which communicates freely with the space above the fuel in the float chamber K, which space is vented to the atmosphere. As the throttle opens, the lever H1 rotates in an anti-clockwise direction (Figure 2), and the lever H3 in a clockwise direct-ion thereby depressing the piston L5.

The movement downward of L5 compresses the spring L4 which abuts against the moveable piston L1. Meanwhile, the piston rod L3 moves downwards with the piston L5. The piston L1 follows L3 downwards, its velocity being determined by the spring L4, by the mass of the piston L1 and by the restriction M. The valve L2 is closed by the pressure created in L and fuel issues from M into D and thus into C. The continued movement of H3 downwards brings it in contact with the valve J which admits an additional fuel supply from the float chamber K into the passage D2, leading into thc'fuel nozzle D.

It will be noted that the level XY of the fuel in the float chamber K is just above the tip of the fuel nozzle M and below the air openings D4 in the nozzle D. A positive head is thus available at all times acting on the outlet from the nozzle M to break the surface tension which, if the nozzle M extended above the level XY of the fuel in K, would dela the discharge of this nozzle until the air fiow through the mixture chamber G was sufiiclently large to create a depression equal to the hydrostatic pressure of a column of fuel equal to the amount the nozzle extended above the level XY plus the surface tension.

What I claim is 1. In a carburetor, a mixing chamber, a constant level fuel supply chamber, a mixture outlet, a throttle valve therein, an air vented fuel nozzle discharging into said mixing chamber comprising a cylindrical chamber, a

' tube in said chamber formin inner and outer concentric chambers, three orizontal shoul-' ders on said tube engaging with the walls of said outer chamber dividing the outer chamber into three sections, passages connecting each of said sections with the inner chamber, an air connection for the upper section, means for intermittently connecting the middle section with the fuel supply chamber when the throttle is opened more than acertain minimum degree, said lower section being in constant communication with said fuel supply chamber, a high s eed fuel nozzle discharging intothe centra chamber at a point slightly below the level in said fuel supply chamber, an unobstructed fuel pasage conmeeting said fuel supply chamber to said nozzle, pump means mechanically operated by the throttle and located in said passage so. as to accelerate the flowthrough said high speed fuel nozzle when the throttle is rapidly opened. v.

2. In acarburetor, a mixin chamber, a constant level fuel supply cham er, a mixture outlet, 2. throttle valve therein, an air vented fuel nozzle dischargin in said mixing chamber, a second fuel nozz e also discharging into said mixing chamber, a normally unobstructed fuel passage connecting said fuel supply chamber to the second nozzle, fuel pump means comprising a cylinder communicat ng with said nozzle, a piston therein, an opening therein, a check valve located in the said opening adapted to freely pass fuel therethrough when the piston is at rest, an elastic connection between the throttle and the piston whereby the opening of the throttle traps the fuel in said passage between said check valve and said nozzle thereby accelerating the flow of fuel through said nozzle during an appreciable interval of time.

3. In a carburetor having a mixing chamber, a throttle valve, a lever connected thereto, a fuel accelerating pump comprising a cylinder having a piston therein, an abutment 111 said cylinder, a compression spring interposed between said throttle lever and said abutment, a second compression spring nterposed between said throttle, and said piston, guide means for said springs, means for admitting fuel to said cylinder, a fuel outlet therefrom discharging into said mixing chamber. V

In testimony whereof I afiix my signature.

BERT BEARD. 

